In general, a window is a space in the wall or the roof of a building, which has glass in it so that air or sunlight can enter and a user can see out.
When a wall is constructed, a portion of the wall is formed so as to be open by placing concrete or laying bricks after first securing a space in which a window frame for installation of a window is installed.
FIG. 1 is a plan view illustrating a general structure in which an exterior insulation material is installed around a window frame on an outer wall of a building.
As shown in FIG. 1, in most cases, an exterior insulation material is installed in a manner such that a window frame 40 and a window 50 are first installed in a wall 10 and an exterior insulation material 20 and an exterior sheathing material 30 are installed on the outer side of the wall.
In order to maintain the indoor temperature constant, the exterior insulation material 20 must be installed between the wall 10 and the exterior sheathing material 30, whereby it is possible to effectively prevent heat loss between an indoor area and an outdoor area, and if the exterior insulation material 20 is exposed to external air, convection heat transfer, in which the heat transfer rate is high, occurs, and consequently heat loss is increased.
However, when the exterior insulation material 20 is installed to the wall 10, as shown in FIG. 1, the exterior insulation material 20 cannot cover the edge of the opening in the wall 10, in which the window frame 40 is installed, and only the exterior sheathing material 30 covers the edge of the opening in the wall 10.
In this case, there is a problem in which heat transfer and resultant heat loss occur more actively in the region of the wall 10 that is not covered with the exterior insulation material 20 than in the region of the wall 10 that is covered with the exterior insulation material 20.
In order to solve this problem, a heat transfer cutoff structure of a window for a building is disclosed in Korean Patent Laid-Open Publication No. 10-2012-0061461, which includes a concrete wall forming an outer wall surface of a building, a window unit installed through the concrete wall, and a heat transfer cutoff member interposed between a sash frame of the window unit and the concrete wall and having a predetermined thickness capable of lowering heat conductivity therebetween, whereby the sash frame of the window unit and the concrete wall are not in direct contact with each other due to the heat transfer cutoff member interposed therebetween, which has the effect of improving the insulation performance of the building.
However, in the above-described prior art, because the heat transfer cutoff member is installed to the opening in the wall and the window frame is installed to the heat transfer cutoff member, there is an inconvenience in that it is difficult to accurately determine the dimensions of the opening in the wall when the same is formed.
Further, in the above-described prior art, because the heat transfer cutoff member must be interposed between the window frame and the wall surface, there is inconvenience in that manufacturing costs are increased and the construction thereof takes a long time.